1. Field of the Invention
The present invention generally relates to an optical disk device, an information processing device, an optical disk recording method, a constant estimating method, and an information recording device, and more particularly, to an optical disk device, an information processing device, an optical disk recording method, a constant estimating method, and an information recording device which record data on a disk-type recording medium, such as a recordable or rewritable optical disk.
2. Description of the Related Art
It is well known that recording formats for an optical disk include a CLV (Constant Linear Velocity) type in which a data row (a data train) on an optical disk is at a constant velocity when viewed from an optical pickup, and a CAV (Constant Angular Velocity) type in which an angular velocity of an optical disk is constant.
As for the optical disk of the format of the CAV type, although it is easy to control the revolution of the disk during a data-recording and a data-reproducing, there is an inconvenience that a density is low at an outer periphery of the disk, and thus a memory capacity cannot be made larger. Therefore, there also exists a recording format such as an MCAV (Modified CAV) type in which the face of an optical disk is divided into a predetermined number of tracks so as to form a plurality of zones, and data is recorded by making an angular velocity and a recording density constant in each zone, and also exists an MCLV (Modified CLV) type. These recording formats are also employed in an MO, etc.
However, many of optical disks used generally at present such as a CD family perform a data-recording with the format of the CLV type having the largest disk capacity. This method increases an error correction capability by interleaving record data; therefore, a continuity of an interleave and a data row needs to be maintained.
When a recording or a reproducing is performed to these optical disks on which data is recorded in the format of the CLV type, a CLV (Constant Linear Velocity) method is mainly used. For the sake of a high-speed data-recording, data is generally recorded at a linear velocity predetermined times as fast as a standard velocity.
In addition, Japanese Laid-Open Patent Application No. 10-49990 and Japanese Laid-Open Patent Application No. 2000-40302 disclose a technology as follows. In this technology, in order to overcome a buffer underrun error in which data is emptied from a buffer memory for a recording so as to disable the continuation of a recording, a pause and a restart of a recording that guarantee the continuity of an interleave and a data row are performed. Upon performing the pause and the restart, an interleave circuit is maintained in a state immediately after the pause of the recording, and when a preparation for the restart is completed, the interleave circuit is caused to operate from a position immediately after the pause so as to record a data row without a discontinuity on the optical disk.
However, as shown in FIG. 2-(a), in the CLV method, since the revolutions of the disk are large in number at the inner periphery of the optical disk, there is an inconvenience that the revolutions of the disk cannot be increased due to a limit of a revolving system at the inner periphery of the optical disk; thus the recording velocity cannot be increased. Inconveniences of the revolving system include not only a limitation due to a mechanical requirement for a high torque, but also an increase in an amount of electric power to be consumed in a spindle motor and a motor driver thereof.
Thereupon, a data-recording by a CAV method has been attempted to be performed, in which an angular velocity of the disk is constant. Upon a data-reproducing, not only the CLV method, but also the CAV method is generally used, in which a transfer rate becomes higher toward the outer periphery of the optical disk. However, the data-recording by the CAV method is not used in general very much, because there are many problems as follows: a laser power required for a data-recording becomes larger as the data-recording proceeds toward the outer periphery of the optical disk, making the control thereof difficult; a recording signal frequency varies continuously within the optical disk, complicating the generation of a recording pulse; etc.
In addition, when a data-recording involves a sharp change of the velocity, a continuity of an interleave and a data row has to be maintained before and after the change. Since a certain amount of time is generally required to stabilize a revolving system of the optical disk, changing the recording velocity sharply during a data-recording may possibly deteriorate the quality of a signal at the recorded part and thus disable the reproduction thereof.
Further, conventionally, since a pause during a data-recording is not allowed to be performed, a data-writing unit becomes large to a certain extent. Therefore, when a transfer of record data from a host computer cannot keep up with the recording velocity, a recording error called buffer-underrun occurs.
Additionally, disk-type recording media with a constant linear velocity include a CD-R (Compact Disk Recordable) disk. Conventionally, this CD-R disk is revolved at a constant linear velocity (CLV) to record data thereon. In this case, a relative velocity between the disk-type recording medium and a laser beam is always constant; therefore, once recording conditions such as a recording power and a record pulse width are set optimally, these recording conditions do not need to be changed throughout the surface of the disk.
Therefore, normally, a test-writing is performed in a specific area at the innermost periphery of the disk, with changing the recording power variously, so as to determine an optimum recording power, with which power a recording can be performed at an equal linear velocity throughout the surface of the disk without causing any problem.
However, in the CLV method, as the recording is performed nearer the inner periphery, the revolution of the disk needs to be made faster, i.e., the angular velocity of the disk needs to be made higher, making it difficult to revolve the disk at such a high speed. This leads to a higher cost of a motor and the increase in noises and vibrations; it also becomes difficult to design other servo systems.
Thereupon, several measures have been taken, in which the angular velocity is not made very low at the outer periphery, while the angular velocity is not made so high at the inner periphery.
In this case, the linear velocity becomes higher nearer the outer periphery. In a case of a complete constant angular velocity (CAV), the linear velocity becomes higher in proportion with the radius of the disk.
In any of the above-mentioned measures, the angular velocity at the inner periphery is not made high; therefore, in some cases, a recording is performed at a velocity different from the velocity at the inner periphery in which a test-writing is performed.
In these cases, how to set or arrange the recording power and other recording conditions is a matter of concern.
Thereupon, conventionally, there has been an information recording device changing a recording power, when performing a recording at an undesired linear velocity, according to a clock frequency in proportion with the linear velocity (for example, see Japanese Laid-Open Patent Application No. 11-296858).
However, the above-mentioned conventional information recording devices cannot perform a high-quality recording unless recording characteristics (i.e., a necessary recording power and other recording conditions) of the disk-type recording medium are completely in proportion with the linear velocity. Essentially, there does not exist such a disk-type recording medium; rather, there are inevitable differences in recording characteristics among various types of disk-type recording mediums.